Plans for a new superhighway in Nigeria's Cross River state are facing criticism from groups that say the road system will put at risk the region's wildlife, including the Cross River gorilla, considered the word's rarest great ape.

The project – currently halted, although some land clearing has already occurred – also has the potential to displace some 180 indigenous communities, according to the Wildlife Conservation Society (WCS), which is leading an effort to put a halt to the new road system.

Upon completion, the highway will have six lanes and cover 162 miles, with 6-mile buffers on both sides. The route moves through protected areas that are home to threatened animals such as elephants, monkees, chimpanzees, pangolins, parrots and crocodiles.

Also in the road's path is habitat key to the Cross River gorilla, a critically endangered great ape geographically cut off by nearly 200 miles from other gorilla populations that survives in a region along the border between Nigeria and Cameroon. Only a couple of hundred are left.

"The proposed highway poses an enormous threat to the cultures and the wildlife of the entire region," said WCS Executive Vice President for Public Affairs John Calvelli, in a statement. His organization is working with the forest stewardship group Ekuri Initiative to gather enough petition signatures to convince the state government to either create a new route for the highway or use funds to improve existing roads.

The drill, an endangered relative of baboons, could see its habitat impacted by a highway proposal in Nigeria. Credit: WCS

According to the WCS, in the crosshairs of the highway are a host of protected areas: Cross River National Park, Ukpon River Forest Reserve, Cross River South Forest Reserve, Afi River Forest Reserve and the Afi Mountain Wildlife Sanctuary.

Preuss's red colobus monkeys, African gray parrots, drills and Nigerian-Cameroon chimpanzees are among the species threatened by the highway project.

Human lives could be disrupted as well. "The project as it stands will displace more than 180 local communities and greatly diminish the country's natural heritage," said WCS Nigeria Director Andrew Dunn, who urged the Cross River government to reconsider the project.